Updated vendors/pypromise submodule
Force serializer to be passed
Updated tests for pygrapes.tasks
pygrapes.serializer.local.Local extends pygrapes.serializer.Adapter
Fixed passing call arguments to command handler
Added examples
Added Json serializer with tests
Added pygrapes.util module (with tests)
Load conditionally all available adapters in order to make them available right inside pygrapes.adapter module
Removed dependencies to other projects from  pygrapes.adapter.zeromq and  pygrapes.adapter.amqp modules
Load pygrapes.serializer.json.Json right inside pygrapes.serializer
Refactored loading json library in pygrapes.serializer.json in order to use pygrapes.util.not_implemented
Added 'sync_task' function to pygrapes.tasks
Added 'pygrapes.grape' utility module; Refactored 'local.py' example to use pygrapes.Grape